HIV-1 protease inhibitors have been successfully used in combination with nucleoside analogs to reduce HIV viral load and increase CD4 counts in patients with HIV-1 infection. A number of studies are underway or planned to determine whether protease inhibitors may be more effective, and the response to these more durable, when administered together. Although there have been a number of studies carried out to examine the pharmacokinetic interactions between several of the protease inhibitors, there is not information regarding the possible effects of concurrent or separate administration of the drugs on their pharmacokinetics. This study is being conducted to determine whether interactions between the HIV-1 protease inhibitors, nelfinavir, ritonavir, and saquinavir are affected by staggering drug administration.